Peer Effects in Drug Use and Sex Among College Students

Past research suggests that congregating delinquent youth increases their likelihood of problem behavior. We test for analogous peer effects in the drug use and sexual behavior of male ( n = 279) and female ( n = 435) college students, using data on the characteristics of first-year roommates to whom they were randomly assigned. We find that males who reported binge drinking in high school drink much more in college if assigned a roommate who also binge drank in high school than if assigned a nonbinge-drinking roommate. No such multiplier effect is observed for females, nor are multiplier effects observed for marijuana use or sexual behavior for either males or females. Students who did not engage in these behaviors in high school do not appear to be affected by their roommates’ high school behavior.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44594/1/10802_2005_Article_3576.pd

Promotion of Hendra virus replication by microRNA 146a

Hendra virus is a highly pathogenic zoonotic paramyxovirus in the genus Henipavirus. Thirty-nine outbreaks of Hendra virus have been reported since its initial identification in Queensland, Australia, resulting in seven human infections and four fatalities. Little is known about cellular host factors impacting Hendra virus replication. In this work, we demonstrate that Hendra virus makes use of a microRNA (miRNA) designated miR-146a, an NF-κB-responsive miRNA upregulated by several innate immune ligands, to favor its replication. miR-146a is elevated in the blood of ferrets and horses infected with Hendra virus and is upregulated by Hendra virus in human cells in vitro. Blocking miR-146a reduces Hendra virus replication in vitro, suggesting a role for this miRNA in Hendra virus replication. In silico analysis of miR-146a targets identified ring finger protein (RNF)11, a member of the A20 ubiquitin editing complex that negatively regulates NF-κB activity, as a novel component of Hendra virus replication. RNA interference-mediated silencing of RNF11 promotes Hendra virus replication in vitro, suggesting that increased NF-κB activity aids Hendra virus replication. Furthermore, overexpression of the IκB superrepressor inhibits Hendra virus replication. These studies are the first to demonstrate a host miRNA response to Hendra virus infection and suggest an important role for host miRNAs in Hendra virus disease

Inhibition of cervical cancer cell growth in vitro and in vivo with dual shRNAs

RNA interference (RNAi)-based gene silencing is widely used in laboratories for gene function studies and also holds a great promise for developing treatments for diseases. However, in vivo delivery of RNAi therapy remains a key issue. Lentiviral vectors have been employed for stable gene transfer and gene therapy and therefore are expected to deliver a stable and durable RNAi therapy. But this does not seem to be true in some disease models. Here, we showed that lentivirus delivered short-hairpin RNA (shRNA) against human papillomavirus (HPV) E6/E7 oncogenes were effective for only 2 weeks in a cervical cancer model. However, using this vector to carry two copies of the same shRNA or two shRNAs targeting at two different but closely related genes (HPV E6 and vascular endothelial growth factor) was more effective at silencing the gene targets and inhibiting cell or even tumor growth than their single shRNA counterparts. The cancer cells treated with dual shRNA were also more sensitive to chemotherapeutic drugs than single shRNA-treated cells. These results suggest that a multi-shRNA strategy may be a more attractive approach for developing an RNAi therapy for this cancer. Cancer Gene Therapy (2011) 18, 219-227; doi: 10.1038/cgt.2010.72; published online 19 November 201

Comparisons of high-risk cervical HPV infections in Caribbean and US populations

<p>Abstract</p> <p>Background</p> <p>Disparities in cervical cancer incidence and mortality rates exist among women of African ancestry (African-American, African-Caribbean and African). Persistent cervical infection with Human papillomavirus (HPV) is associated with cervical dysplasia and if untreated, could potentially progress to invasive cervical cancer. Very few studies have been conducted to examine the true prevalence of HPV infection in this population. Comparisons of cervical HPV infection and the type-specific distribution of HPV were performed between cancer-free Caribbean and US women.</p> <p>Results</p> <p>The Caribbean population consisted of 212 women from Tobago and 99 women from Jamaica. The US population tested, consisted of 82 women from Pittsburgh. The majority of the US subjects was Caucasian, 74% (61/82) while 12% (10/82) and 13% (11/82) were African-American or other ethnic groups, respectively. The age-adjusted prevalence of any HPV infection among women from Tobago was 35%, while for Jamaica, it was 81% (p < 0.0001). The age-adjusted prevalence of HPV infection for Caribbean subjects was not statistically significantly different from the US (any HPV: 47% vs. 39%, p > 0.1; high-risk HPVs: 27% vs. 25%, p > 0.1); no difference was observed between US-Blacks and Jamaicans (any HPV: 92% vs. 81%, p > 0.1; high-risk HPV: 50% vs. 53%, p > 0.1). However, US-Whites had a lower age-adjusted prevalence of HPV infections compared to Jamaican subjects (any HPV: 29% vs. 81%, p < 0.0001; high-risk HPV: 20% vs. 53%, p < 0.001). Subjects from Jamaica, Tobago, and US-Blacks had a higher proportion of high-risk HPV infections (Tobago: 20%, Jamaica: 58%, US-Blacks: 40%) compared to US-Whites (15%). Similar observations were made for the presence of infections with multiple high-risk HPV types (Tobago: 12%, Jamaica: 43%, US-Blacks: 30%, US-Whites: 8%). Although we observed similar prevalence of HPV16 infections among Caribbean and US-White women, there was a distinct distribution of high-risk HPV types when comparisons were made between the ethnic groups.</p> <p>Conclusion</p> <p>The higher prevalence of cervical HPV infections and multiple high-risk infections in Caribbean and US-Black women may contribute to the high incidence and prevalence of cervical cancer in these populations. Evaluation of a larger sample size is currently ongoing to confirm the distinct distribution of HPV types between ethnic groups.</p

Phage-Induced Expression of CRISPR-Associated Proteins Is Revealed by Shotgun Proteomics in Streptococcus thermophilus

The CRISPR/Cas system, comprised of clustered regularly interspaced short palindromic repeats along with their associated (Cas) proteins, protects bacteria and archaea from viral predation and invading nucleic acids. While the mechanism of action for this acquired immunity is currently under investigation, the response of Cas protein expression to phage infection has yet to be elucidated. In this study, we employed shotgun proteomics to measure the global proteome expression in a model system for studying the CRISPR/Cas response in S. thermophilus DGCC7710 infected with phage 2972. Host and viral proteins were simultaneously measured following inoculation at two different multiplicities of infection and across various time points using two-dimensional liquid chromatography tandem mass spectrometry. Thirty-seven out of forty predicted viral proteins were detected, including all proteins of the structural virome and viral effector proteins. In total, 1,013 of 2,079 predicted S. thermophilus proteins were detected, facilitating the monitoring of host protein synthesis changes in response to virus infection. Importantly, Cas proteins from all four CRISPR loci in the S. thermophilus DGCC7710 genome were detected, including loci previously thought to be inactive. Many Cas proteins were found to be constitutively expressed, but several demonstrated increased abundance following infection, including the signature Cas9 proteins from the CRISPR1 and CRISPR3 loci, which are key players in the interference phase of the CRISPR/Cas response. Altogether, these results provide novel insights into the proteomic response of S. thermophilus, specifically CRISPR-associated proteins, upon phage 2972 infection

Novel HIV-1 Knockdown Targets Identified by an Enriched Kinases/Phosphatases shRNA Library Using a Long-Term Iterative Screen in Jurkat T-Cells

HIV-1 is a complex retrovirus that uses host machinery to promote its replication. Understanding cellular proteins involved in the multistep process of HIV-1 infection may result in the discovery of more adapted and effective therapeutic targets. Kinases and phosphatases are a druggable class of proteins critically involved in regulation of signal pathways of eukaryotic cells. Here, we focused on the discovery of kinases and phosphatases that are essential for HIV-1 replication but dispensable for cell viability. We performed an iterative screen in Jurkat T-cells with a short-hairpin-RNA (shRNA) library highly enriched for human kinases and phosphatases. We identified 14 new proteins essential for HIV-1 replication that do not affect cell viability. These proteins are described to be involved in MAPK, JNK and ERK pathways, vesicular traffic and DNA repair. Moreover, we show that the proteins under study are important in an early step of HIV-1 infection before viral integration, whereas some of them affect viral transcription/translation. This study brings new insights for the complex interplay of HIV-1/host cell and opens new possibilities for antiviral strategies

In silico modeling indicates the development of HIV-1 resistance to multiple shRNA gene therapy differs to standard antiretroviral therapy

<p>Abstract</p> <p>Background</p> <p>Gene therapy has the potential to counter problems that still hamper standard HIV antiretroviral therapy, such as toxicity, patient adherence and the development of resistance. RNA interference can suppress HIV replication as a gene therapeutic via expressed short hairpin RNAs (shRNAs). It is now clear that multiple shRNAs will likely be required to suppress infection and prevent the emergence of resistant virus.</p> <p>Results</p> <p>We have developed the first biologically relevant stochastic model in which multiple shRNAs are introduced into CD34+ hematopoietic stem cells. This model has been used to track the production of gene-containing CD4+ T cells, the degree of HIV infection, and the development of HIV resistance in lymphoid tissue for 13 years. In this model, we found that at least four active shRNAs were required to suppress HIV infection/replication effectively and prevent the development of resistance. The inhibition of incoming virus was shown to be critical for effective treatment. The low potential for resistance development that we found is largely due to a pool of replicating wild-type HIV that is maintained in non-gene containing CD4+ T cells. This wild-type HIV effectively out-competes emerging viral strains, maintaining the viral <it>status quo</it>.</p> <p>Conclusions</p> <p>The presence of a group of cells that lack the gene therapeutic and is available for infection by wild-type virus appears to mitigate the development of resistance observed with systemic antiretroviral therapy.</p

Barrier-to-Autointegration Factor Proteome Reveals Chromatin-Regulatory Partners

Nuclear lamin filaments and associated proteins form a nucleoskeletal (“lamina”) network required for transcription, replication, chromatin organization and epigenetic regulation in metazoans. Lamina defects cause human disease (“laminopathies”) and are linked to aging. Barrier-to-autointegration factor (BAF) is a mobile and essential component of the nuclear lamina that binds directly to histones, lamins and LEM-domain proteins, including the inner nuclear membrane protein emerin, and has roles in chromatin structure, mitosis and gene regulation. To understand BAF's mechanisms of action, BAF associated proteins were affinity-purified from HeLa cell nuclear lysates using BAF-conjugated beads, and identified by tandem mass spectrometry or independently identified and quantified using the iTRAQ method. We recovered A- and B-type lamins and core histones, all known to bind BAF directly, plus four human transcription factors (Requiem, NonO, p15, LEDGF), disease-linked proteins (e.g., Huntingtin, Treacle) and several proteins and enzymes that regulate chromatin. Association with endogenous BAF was independently validated by co-immunoprecipitation from HeLa cells for seven candidates including Requiem, poly(ADP-ribose) polymerase 1 (PARP1), retinoblastoma binding protein 4 (RBBP4), damage-specific DNA binding protein 1 (DDB1) and DDB2. Interestingly, endogenous BAF and emerin each associated with DDB2 and CUL4A in a UV- and time-dependent manner, suggesting BAF and emerin have dynamic roles in genome integrity and might help couple DNA damage responses to the nuclear lamina network. We conclude this proteome is a rich source of candidate partners for BAF and potentially also A- and B-type lamins, which may reveal how chromatin regulation and genome integrity are linked to nuclear structure

Nuclear Factor-Kappa B Family Member RelB Inhibits Human Immunodeficiency Virus-1 Tat-Induced Tumor Necrosis Factor-Alpha Production

Human Immunodeficiency Virus-1 (HIV-1)-associated neurocognitive disorder (HAND) is likely neuroinflammatory in origin, believed to be triggered by inflammatory and oxidative stress responses to cytokines and HIV protein gene products such as the HIV transactivator of transcription (Tat). Here we demonstrate increased messenger RNA for nuclear factor-kappa B (NF-κB) family member, transcription factor RelB, in the brain of doxycycline-induced Tat transgenic mice, and increased RelB synthesis in Tat-exposed microglial cells. Since genetic ablation of RelB in mice leads to multi-organ inflammation, we hypothesized that Tat-induced, newly synthesized RelB inhibits cytokine production by microglial cells, possibly through the formation of transcriptionally inactive RelB/RelA complexes. Indeed, tumor necrosis factor-alpha (TNFα) production in monocytes isolated from RelB deficient mice was significantly higher than in monocytes isolated from RelB expressing controls. Moreover, RelB overexpression in microglial cells inhibited Tat-induced TNFα synthesis in a manner that involved transcriptional repression of the TNFα promoter, and increased phosphorylation of RelA at serine 276, a prerequisite for increased RelB/RelA protein interactions. The Rel-homology-domain within RelB was necessary for this interaction. Overexpression of RelA itself, in turn, significantly increased TNFα promoter activity, an effect that was completely blocked by RelB overexpression. We conclude that RelB regulates TNFα cytokine synthesis by competitive interference binding with RelA, which leads to downregulation of TNFα production. Moreover, because Tat activates both RelB and TNFα in microglia, and because Tat induces inflammatory TNFα synthesis via NF-κB, we posit that RelB serves as a cryoprotective, anti-inflammatory, counter-regulatory mechanism for pathogenic NF-κB activation. These findings identify a novel regulatory pathway for controlling HIV-induced microglial activation and cytokine production that may have important therapeutic implications for the management of HAND